Re: [PATCH 09/44] perf session: Add instruction tracing options

From: Arnaldo Carvalho de Melo
Date: Thu Apr 23 2015 - 10:09:07 EST


Em Wed, Apr 22, 2015 at 09:23:09AM +0300, Adrian Hunter escreveu:
> On 21/04/15 17:50, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Apr 09, 2015 at 06:53:49PM +0300, Adrian Hunter escreveu:
> >
> >> It is assumed that AUX area decoding will synthesize events for
> >> consumption by other tools. At this time, the main use of AUX area
> >> tracing will be to capture instruction trace (aka processor trace)
> >> data. The nature of instruction tracing suggests the initial
> >> inclusion of options for "instructions" and "branches" events, but
> >> more could be added as needed.
> >
> >> +++ b/tools/perf/util/auxtrace.c
> >> @@ -37,6 +37,7 @@
> >>
> >> #include "event.h"
> >> #include "debug.h"
> >> +#include "parse-options.h"
> >>
> >> int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
> >> struct auxtrace_mmap_params *mp,
> >> @@ -200,6 +201,136 @@ out_free:
> >> return err;
> >> }
> >>
> >> +#define PERF_ITRACE_DEFAULT_PERIOD_TYPE PERF_ITRACE_PERIOD_NANOSECS
> >> +#define PERF_ITRACE_DEFAULT_PERIOD 100000
> >> +#define PERF_ITRACE_DEFAULT_CALLCHAIN_SZ 16
> >> +#define PERF_ITRACE_MAX_CALLCHAIN_SZ 1024
> >> +
> >> +void itrace_synth_opts__set_default(struct itrace_synth_opts *synth_opts)
> >> +{
> >> + synth_opts->instructions = true;
> >> + synth_opts->branches = true;
> >> + synth_opts->errors = true;
> >> + synth_opts->period_type = PERF_ITRACE_DEFAULT_PERIOD_TYPE;
> >> + synth_opts->period = PERF_ITRACE_DEFAULT_PERIOD;
> >> + synth_opts->callchain_sz = PERF_ITRACE_DEFAULT_CALLCHAIN_SZ;
> >> +}
> >> +
> >> +int itrace_parse_synth_opts(const struct option *opt, const char *str,
> >> + int unset)
> >> +{
> >> + struct itrace_synth_opts *synth_opts = opt->value;
> >> + const char *p;
> >> + char *endptr;
> >> +
> >> + synth_opts->set = true;
> >> +
> >> + if (unset) {
> >> + synth_opts->dont_decode = true;
> >> + return 0;
> >> + }
> >> +
> >> + if (!str) {
> >> + itrace_synth_opts__set_default(synth_opts);
> >> + return 0;
> >> + }
> >> +
> >> + for (p = str; *p;) {
> >> + switch (*p++) {
> >> + case 'i':
> >> + synth_opts->instructions = true;
> >
> > Is this documented anywhere? I.e. examples for setting up this synth
> > ops?
>
> They are documented for each tool that uses them:
> Documentation/perf-script.txt
> Documentation/perf-record.txt
> and also in:
> Documentation/intel-pt.txt

That comes later in the patchkit, right? I am ammending this patch to
put a reference to these files, which ammeliorates the current
situation, but people doing bisects will scratch their heads...

- Arnaldo
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